1. Technical Field
The present disclosure relates to an LED lighting apparatus, and more particularly, to a control circuit for an LED lighting apparatus, which is capable of improving power efficiency.
2. Related Art
A lighting apparatus is designed to use a light source which exhibits high light emission efficiency using a small amount of energy, in order to reduce energy consumption. Representative examples of a light source used in the lighting apparatus may include an LED.
The LED is different from other light sources in terms of various aspects such as energy consumption, lifetime, and light quality. However, since the LED is driven by a current, a lighting apparatus using the LED as a light source requires a large number of additional circuits for driving a current.
In order to solve the above-described problem, an AC direct-type lighting apparatus has been developed to provide an AC voltage to an LED. The lighting apparatus is configured to convert an AC voltage into a rectified voltage, and drive a current using the rectified voltage such that the LED emits light. The rectified voltage indicates a voltage obtained by full-wave rectifying an AC voltage. Since the lighting apparatus directly uses a rectified voltage without using an inductor and a capacitor, the lighting apparatus has a satisfactory power factor.
The lighting apparatus using LEDs includes a driver which provides a current path for a driving current in response to light emission based on the change of the rectified voltage. The lighting apparatus may further include an additional device for controlling a light emitting state, such as a dimming circuit or wireless module.
In this case, the additional device requires an operating voltage for operation. The additional device requires a constant voltage of 2V to 5V as the operating voltage.
The above-described lighting apparatus may use an external voltage or a voltage which is separately generated through a power supply, as the operating voltage of the additional device. When the lighting apparatus is configured to provide the operating voltage of the additional device, the power efficiency of the lighting apparatus is inevitably degraded.
Thus, there is a demand for the development of a lighting apparatus which is capable of reducing power consumption while having high power efficiency.